Ghostknife
Goblin Guru
Vibrant makes short resonators, maybe add one in the section below the muffler?
It's very loud
- Thread starter PHENDERSON
- Start date
Dsteinhorst
Well-Known Member
You may benefit from downsizing to a 2" exhaust that DF sends with the N/A kits. I went from a 2" to a 3" and there was a HUGE increase in noise. I believe the forced induction donors got a 2.5"
Rttoys
Goblin Guru
Advice #1. Don’t pack the muffler too tight and not secure it properly. The packing may move, plug the exhaust, then blow the muffler up. Ask me how I know?
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Fozda
Goblin Guru
Ecotecs might not be very unique but the location and available space for a muffler in the Goblin is fairly unique...
Scott #321
Well-Known Member
My issue is the intake noise on my tc Goblin being directly behind the passenger seat.
Ark :D
Goblin Guru
Interesting, this is one of the things I like MOST about mine.
These have more room than a VW dune buggy with their rear engine, and if a bigger muffler was needed there, the pipe from the header was extended further to the side of the car and then curved into the larger muffler, which also extended further to the opposite side.
A Goblin has more room to the rear of its mid-located engine, and similar methods to the above dune buggy example can be used. Just need to be creative....
Fozda
Goblin Guru
Sounds like you're describing a whole new exhaust system instead of just a simple muffler replacement...
Desert Sasqwatch
Goblin Guru
Some of the ideas put forth have their merits, but let's all keep in mind @PHENDERSON doesn't have a welder. So I'm assuming the solution he is looking for wouldn't involve fabrication and welding together pipes and mufflers.
Exhaust inserts, which reduce noise, also impede exhaust flow - but this may be his option if no welding can be done. So it becomes a trade off for low dBs versus less 'fun factor', but still being able to DIY a quieter exhaust..
Exhaust inserts, which reduce noise, also impede exhaust flow - but this may be his option if no welding can be done. So it becomes a trade off for low dBs versus less 'fun factor', but still being able to DIY a quieter exhaust..
Waterdriver
Goblin Guru
Another option is Supertrapp. It's tunable so you can get you desired noise suppression while increasing back pressure and reducing power. But can always add discs back in when needed or remove altogether.
Dale E
Well-Known Member
So tell me what engine you have and if you have the stock exhaust header or an aftermarket one - short or long -- tuned equal length? Is it a 2 1/2 outlet to muffler pipe or 3 inch out? Does it go straight out the back like @Rttoys? or does it exit to the drivers side like some of the turbo cars? Do you want a single exit muffler pipe or a center twin, or outside twin exits? How much quieter do you want it? Do you want high pitch (rice rocket sound) or a low rumble old school hotrod sound?
Intakes also cause noise situations. The Dual side draft Weber carbs on my Birkin make more noise sucking air in than the exhaust. Listen to some videos of European hill climb cars and those bike carbureted, individual throttle body (roller and slider actuated ones too) cars make some screaming noises (they also run at high RPM).. People take notice when the Birkin is running. It also produces a different total sound.
Mufflers are just like engines and can be tuned to a certain sound, but it might take a few different muffler builds or combinations to get you there. And the way you drive also is a factor. Easy on the throttle and it will be quieter than always flooring it.
You don't want to impede air flow and create too much back pressure. You don't want to big of piping either.
There are many different configurations you can choose -- auger type, perforated cone type (@Desert Sasqwatch), Perforated pipe (straight through or a few internal to the muffler body (( those usually chambered as well )) with or without deadening wraps, baffled type like Flowmaster. There are ones with half circles (Spintech) and there used to be a Wave muffler (internal washboard baffles). The old dimpled side pipes of years gone by. There are also disc type inserts like the cone insert. You also have to consider the engine RPM range you normally drive for exhaust tuning (you can always have a quiet street muffler with an open flow vacuum, electric or manual operation. (old school cutout type). Sine, Sawtooth, Square wave sounds create differences and Frequency/Hz ranges. Whew!!
Take for instance a 3.4 GM V6 (which is basically a 350 V8 minus two cylinders) and it sounds close to a 350 V8 if you muffler it right. The 3.8 GM V6 has a totally different sound and people have a disturbingly hard time getting it to sound good.
A few Goblin builders have created some visual works of art for exhaust and like you as a builder it was their individual preference.
Bottom line: If you find a solution that works for you, then make it happen. You are the one that is driving the Goblin, it is yours, and you apparently want to honor your neighbors sensitivities as well as your own.
Intakes also cause noise situations. The Dual side draft Weber carbs on my Birkin make more noise sucking air in than the exhaust. Listen to some videos of European hill climb cars and those bike carbureted, individual throttle body (roller and slider actuated ones too) cars make some screaming noises (they also run at high RPM).. People take notice when the Birkin is running. It also produces a different total sound.
Mufflers are just like engines and can be tuned to a certain sound, but it might take a few different muffler builds or combinations to get you there. And the way you drive also is a factor. Easy on the throttle and it will be quieter than always flooring it.
You don't want to impede air flow and create too much back pressure. You don't want to big of piping either.
There are many different configurations you can choose -- auger type, perforated cone type (@Desert Sasqwatch), Perforated pipe (straight through or a few internal to the muffler body (( those usually chambered as well )) with or without deadening wraps, baffled type like Flowmaster. There are ones with half circles (Spintech) and there used to be a Wave muffler (internal washboard baffles). The old dimpled side pipes of years gone by. There are also disc type inserts like the cone insert. You also have to consider the engine RPM range you normally drive for exhaust tuning (you can always have a quiet street muffler with an open flow vacuum, electric or manual operation. (old school cutout type). Sine, Sawtooth, Square wave sounds create differences and Frequency/Hz ranges. Whew!!
Take for instance a 3.4 GM V6 (which is basically a 350 V8 minus two cylinders) and it sounds close to a 350 V8 if you muffler it right. The 3.8 GM V6 has a totally different sound and people have a disturbingly hard time getting it to sound good.
A few Goblin builders have created some visual works of art for exhaust and like you as a builder it was their individual preference.
Bottom line: If you find a solution that works for you, then make it happen. You are the one that is driving the Goblin, it is yours, and you apparently want to honor your neighbors sensitivities as well as your own.
Take it to a muffler shop. They usually have an assortment of mandrel bends (at least the ones around here do) and mufflers so they can put together something that will still flow.... quietly.
Robinjo
Goblin Guru
I'm sure a generic bolt in silencer plug could be bought and installed easily to accommodate this. I might just get on for the cruising around the neighborhood stuff, then take it out when you want performance.Some of the ideas put forth have their merits, but let's all keep in mind @PHENDERSON doesn't have a welder. So I'm assuming the solution he is looking for wouldn't involve fabrication and welding together pipes and mufflers.
Exhaust inserts, which reduce noise, also impede exhaust flow - but this may be his option if no welding can be done. So it becomes a trade off for low dBs versus less 'fun factor', but still being able to DIY a quieter exhaust..
ZZP 2.5" Exhaust Cone Insert Sound Reducer
This cone insert can be fitted inside your existing exhaust to bring down the volume without the need for extra resonators or mufflers. This insert fits directly into your exhaust, these slip fit in but you'll want to either use the integrated nut or tack weld them in. One cone will typically...
zzperformance.com
Desert Sasqwatch
Goblin Guru
JINX: That's the same insert I suggested in post #10.I'm sure a generic bolt in silencer plug could be bought and installed easily to accommodate this. I might just get on for the cruising around the neighborhood stuff, then take it out when you want performance.
ZZP 2.5" Exhaust Cone Insert Sound Reducer
This cone insert can be fitted inside your existing exhaust to bring down the volume without the need for extra resonators or mufflers. This insert fits directly into your exhaust, these slip fit in but you'll want to either use the integrated nut or tack weld them in. One cone will typically...